I have a 2004 Supercab 6 1/2 box with 4FX package, 5.4 engine also 18 wheels. I did a search and found other people with same problem, my cruise control does not hold going down hills even if overdrive off, have increased 15 MPH before braking. The truck almost feels like it free-wheels. We also have a 02 Escape and 99 F 350 diesel neither does this to extent F 150 does. Dealer said was normal for Fords told him my others did not do it, said he would check into it have not heard from him 3 days. Anyone have idea ???? Thanks Dan

 

I assume your under warrenty so make a lot of noise.
Cruise is useless if it is going to work that way.
Ask abou a TSB on it. There must be one with the fix by now.

 

You guys are kidding, right?

 

So it is building speed because it is still accelerating!?
Or
Is it coasting-up to these speeds? (What’s the tach doing?)

 

Yeah, the tach would be a indicator of a problem, not the speedometer.

Going downhill:
If the vehicle speed increases and the tach increases
then take it up with your Ford Service Technician
but
if the vehicle speed increases and the tach decreases,
take it up with Sir Issac Newton.

There is no 'braking' function in the cruise control.

 

You had me on the floor with that one, Raoul! Well said.

 

I don't yet know if there is a brakeing function in cruise but my 02 Screw keep it's speed down hill within about 3 mph.
If anyone has to use the brakes, it automaticly knocks Cruise Control to OFF, then there "really" is little braking function by the engine through the transmission, then..
In an electric control transmission, there is a feature little known about. In many, as soon as the throttle is lifted, the trans comes out of lockup by design. It is a timed function to prevent the lockup from continuing to pull the vehichle when coming to a stop.
Often this action can be seen by watching the tach if equipped.
Let off, then back on the throttle, the tack will go upward, then back down as the PCM reapplied the lockup in just a couple seconds or so. Same if the brake is just tapped even while you have a steady throttle applied.
In older vehichles, the VSS gets in on the act.
Today is may be done differently.